So i'm driving from Pa to Tempe next week and i have some questions.

1. Will it kill me to use regular instead of premium on this trip? By using regular i'm going to saving a good 21 dollars on gas. I'm not going to be in boost at all and it'll be all highway. Would i have any problems?

2. What do you think i will average mpg wise? I've been told guys have been getting 30+mpg on the highway. What do you guys think? Think i can pull 30 or even 32?

 

Mythbuster's had a cool show where they drove a Dodge Charge behind a big 18-wheeler and boosted fuel economy by like 12MPG, went from around 29 to an amazing 42. As long as reaction times are good, you're careful, and you have some good driving experience, I'd say this would be a great way to get there. Not to mention big trucks are allowed to go over the speed limit by 10 or so without catching the eye of cops so you might get there a tiny bit quicker without getting any tickets.

Cruise control will definetly help alot if you have it.


I don't think Cobalt's are built anything higher then 91, so I'd say 87-88 octane would be just fine. (Disclaimer, double check with a dealer or multiple ones to confirm)

 

To get their 41mpg [not 42] they had to be TWO feet from the semi. Not only is that beyond dangerous, it's beyond stupid.

You get a mpg boost at 100 feet [they got 11%, since our cars don't have much in common the Charger the difference could be more or less] and didn't test again till 50 feet, which is starting to get a little close [they WANT to see you and are in a much bigger, heavier vehicle.. a lot of drivers will slow down so that you get mad and pass them, at least here they do].

 

I don't think i want to try and draft a semi at 2 feet. May try the 10-20 feet thing tho.

 

The fuel economy went down when they increased from 50ft to 2ft because there is a tiny bit more wind resistence because of the wind underneath the semi.


Anyways, ya, try draftin it at 75-100ft. it should be enough room for them to see you, and its a safe distance. as long as you have half-decent reflexes and know how to brake. you're braking distance is prob half that of a semi, esp a fully loaded one.

 

I would just keep using the premium gas. Saving $21 isn't really that big of a deal. I went from Denver to L.A. last September and I think I filled up five times both dirsctions, gonna do it again first week of September. I never once thought twice about using regular because the cars manual recommends premium.

You will run accross a few stations that are charging upwards of $3.50 or even $3.60 just because they are in the middle of nowhere and well, people gotta fill up. If that $21 really means alot, go ahead and use regular, I just won't do it to my car.

I had a Camaro that in the owners manual mentioned it recommended 87 octane but I didn't read that part and always used regular.After a year it had a horrible ping that I could never get rid of no matter how long I used premium. I learned my lesson!

 

That's because he probably beat on it when using 87 octane. I don't plan on going into boost but whatever. I'll think about it but i'm not going to be paranoid if i use 87 for the trip. If i was doing redline full WOT runs then yeah i would be but for just setting the cruise and forgetting it.. No big deal.

 

Lower octane could also mean less mpg's since the engine was designed to run on premium for maximum efficiency. Try avoiding highways with huge crosswinds if possible as well.

 

QFT, your mpg will go down if you use less then the recomended octane.

 

They used a Dodge Magnum and it had a V6.
at 55mph no truck 32 mpg
at 55mph 100' 35.5 mpg following kinda close
at 55mph 50' 38.5 mpg you are an idoit
at 55 mph 10' 44.5mpg you are sucidial

You can get better milage, but you can loose you life if you follow this close. About 50% of accidents are caused by following too close.

 

keep it under 80 mph and you should see 30+ mpg. if you keep it under 70 it would be even better.
I'd say at least use 91. but if you must go lower, dont get 87.. do 89.

this is a valid point. octane has something to do with resistance to combustion. lower octane will ignite sooner

 

Haha, try following those trucks and tell me how many rock chips you have on your hood/front bumper after the trip.

 

I've had an authentic JDM S13 Silvia (Right Hand Drive and everything) that was totalled by a BMW following too closely, less than a year later I had an S13 convertible totalled by a Toyota Pickup that wasn't paying attention and didn't even bother to try and stop...the moral: DON'T TAILGATE!

Also, I wouldn't use less than the manufacturer's recommend octane unless you have no choice. Any money you save from the cheaper fuel will be offset by the worse fuel economy. So you won't be saving any money and will be stuck with less power.

 

iv'e made the trip cross country 4 times in my balt, stick with the premium gas, it won't hurt the engine but it will pull timing to accomodate the lower octane.

and yes you will probably be bossting some of the time at least going up grades, and passing, especially if you use the cruise control.

as far as mpg i got as high as 35 mpg one one of my trips, never lower than 32 mpg average.